/Engine/Source/Editor/SequencerCore/Public/MVVM/Selection/SequencerCoreSelection.h
Add a selection set to this class - selection set should be a member of the derived implementation of this class so as to ensure its lifetime matches this owner
void AddSelectionSet ( [FSelectionBase](API\Editor\SequencerCore\MVVM\Selection\FSelectionBase) * InSelection )